fix: 解決kafka會遺漏commit已處理的meesage的問題

GeoPulse Pipeline/KafkaConsumer.cs

@@ -64,8 +64,9 @@ public class KafkaConsumer : BackgroundService
 
 					await BulkInsertToDatabaseAsync(buffer, stoppingToken);
 
-					var latestOffset = buffer.Last();
-					consumer.Commit(latestOffset);
+					var offsets = buffer.GroupBy(msg => msg.TopicPartition)
+						.Select(g => new TopicPartitionOffset(g.Key, g.Last().Offset + 1)).ToList();
+					consumer.Commit(offsets);
 
 					_logger.LogInformation($"✅ [成功] 已寫入 {buffer.Count} 筆資料至 PostgreSQL。");